.box {
       display: flex;
       flex-wrap: wrap;
       width: 100%;
     }
     .box div {
        width: calc(100% / 4);
        height: 100px;
     }

     /* grid */
     .box {
        display: grid;
        grid-template-columns: 1fr 1fr 1fr;
        width: 100%;
     }

     .box div {
        height: 200px;
        text-align:center;
     }
     .box p{
     }
     .mycontent{
       width:100%;
       height:650px;
     }